In enzymology, N5-(carboxyethyl)ornithine synthase () is an enzyme that catalyzes the chemical reaction
The three substrates of this enzyme are N5-(L-1-carboxyethyl)-L-ornithine, oxidised nicotinamide adenine dinucleotide phosphate (NADP<sup>+</sup>), and water. Its products are L-ornithine, reduced NADPH, pyruvic acid, and a proton.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is N5-(L-1-carboxyethyl)-L-ornithine:NADP+ oxidoreductase (L-ornithine-forming). Other names in common use include 5-N-(L-1-carboxyethyl)-L-ornithine:NADP+ oxidoreductase, and (L-ornithine-forming).